I suspect that its not (or not just) the government that XM is worried about.

Back when O&A were signed by XM, XM made them a "premium" channel. If customers wanted to hear them, they had to pay extra.

Then Sirius signed Stern, who'd be available to all their subscribers. XM couldn't get away with charging a premium for a 2nd rate version of what was part of basic service at Sirius. So Opie and Anthony were moved to be part of the regular XM Service.

But I suspect that O&A's contract was still in effect, and they were still being paid as if they were bringing in premium fees. This makes them less valuabe to XM. XM may have taken the incident to as an opportunity to dum them